Scaffold construction apparatus and method

ABSTRACT

Two ladders are connected together with cross-braces to form a scaffold. Platforms of the scaffold are supported on rungs of the ladders. A C-shaped bracket connects to the ladder legs. The bracket has an ear for connecting a brace.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The benefit of provisional application No. 60/185,072 filed Feb.25, 2000 is claimed. Provisional application No. 60/185,072 filed Feb.25, 2000 is incorporated herein by reference.

BACKGROUND OF THE INVENTION FIELD OF THE INVENTION

[0002] The present invention relates to scaffolds, and to cross-bracingof structures.

SUMMARY OF THE INVENTION

[0003] Commonly available scaffolding is expensive and requires a largeamount of space for storage. What is needed is an apparatus which cantemporarily convert existing ladders to scaffolds. Thus would be lessexpensive than purchasing regular scaffolding, because a person can useladders that he or she already owns, and which can still be used asladders when scaffolding is not required. Storage space would belessened, because in addition to the ladders which would have to bestored anyway, one would only need to store the cross-braces, thehardware which connects the cross-braces to the ladders, and theplatforms.

[0004] Scaffold construction apparatus of the present invention includesbraces, brackets, fasteners and platforms, which are provided forcreating a scaffold using two ladders, positioned with broad sidesthereof facing each other, in parallel relationship to each other.

[0005] Braces are combined in pairs to form cross-shaped first andsecond brace structures connected to one another at their crossovers, inthis example at the centers thereof, by fasteners. The first bracestructure spans between and connects to the first and second ladders.The second brace structure spans between and connects to the first andsecond ladders and is positioned opposite the first brace structure. Thefirst and second brace structures are attached along the ladders inpairs, as often as required to create a sturdy structure. Each of thebrackets comprises two opposed end plates, and a side plate which spansbetween and connects the end plates. An ear extends outwardly from theside plate. One of the brackets is fastened to each end of each of thebraces by inserting a fastener through an aperture in the ear.

[0006] The brackets are attached to the ladder legs by positioning theside plate on an outward facing side of the leg, and directing the endplates inward. Fasteners are inserted through apertures in the endplates such that one of the fasteners extends across and above a rung ofthe ladder, and another of the fasteners extends across and below therung of the ladder. This particular positioning of the fasteners throughthe end plates fixes the bracket to the rung and ensures that the bracescannot slip beyond the rungs in either an upward or a downwarddirection. The platforms rest on the rungs of the ladders and spanbetween the ladders.

[0007] Still further features and advantages will become apparent fromthe ensuing description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]FIG. 1 is a partial perspective view showing a scaffoldconstruction apparatus of the present invention installed on portions oftwo ladders.

[0009]FIG. 2 is a complete elevational view of the scaffold constructionapparatus installed on two ladders on level ground.

[0010]FIG. 2A is a view as in FIG. 2 of the scaffold constructionapparatus installed on two ladders on sloping ground.

[0011]FIG. 3 is an enlarged, exploded, partial perspective view showingthe bracket of the scaffold construction apparatus.

[0012]FIG. 4 is an enlarged partial perspective view showing the bracketinstalled on one of the ladders.

[0013]FIG. 5 is a schematic top view of the scaffold assembly of FIG. 2alongside a building also viewed from above.

[0014]FIG. 6 is a schematic top view of portions of two of the scaffoldassemblies of FIG. 2, arranged at the corner of a building also viewedfrom above.

[0015]FIG. 7 is a schematic top view of the scaffold assembly of FIG. 2arranged between two buildings also viewed from above.

DETAILED DESCRIPTION

[0016]FIG. 1 is a partial perspective view showing a scaffoldconstruction apparatus 10 of the present invention installed on portionsof first and second ladders 12, 14. FIG. 2 is a complete elevationalview of scaffold construction apparatus 10 installed on the ladders 12,14, to create a scaffold composed of apparatus 10 and the ladders 12,14. FIG. 3 is a partial exploded perspective view showing a bracket 16of the scaffold construction apparatus 10.

[0017] Referring to the figures, the apparatus 10 comprises a pluralityof the brackets 16, fasteners 18, and braces 20. Platforms 22 areadapted to span between and rest upon rungs 12A, 14A of the ladders 12,14.

[0018] The ladders 12, 14 are positioned with broad sides 12B, 14Bthereof facing each other, in parallel relationship to each other. Eachof the ladders 12, 14 has a first leg 12C, 14C and a second leg 12D,14D. The first legs 12C, 14C are positioned opposite each other. Thesecond legs 12D, 14D are positioned opposite each other.

[0019] The braces 20 are combined in pairs to form cross-shaped firstand second brace structures 24, 26 connected at centers thereof by thefasteners 18, which may comprise conventional carriage bolts, lockwashers and wing nuts. The first brace structure 24 spans between andconnects to the first legs 12C, 14C of the first and second ladders 12,14. The second brace structure 26 spans between and connects to thesecond legs 12D, 14D of the first and second ladders 12, 14, and ispositioned opposite the first brace structure 24.

[0020] The first and second brace structures 24, 26 are attached alongthe ladders 12, 14 in pairs, as often as required to create a sturdystructure. For example, in FIG. 2, each ladder is 20-feet long, andthere are two pairs of cross-brace structures 24, 26, one pair for each10-feet of ladder length.

[0021]FIG. 4 is an enlarged perspective view showing the bracket 16installed on the first ladder 12. Referring now primarily to FIGS. 3 and4, each of the brackets 16 comprises two opposed end plates 16A, and aside plate 16B which spans between and connects the end plates 16A. Theend plates 16A and the side plate 16B together, generally form a C-shapehaving an open side 16C opposite the side plate 16B. An ear 16D extendsoutwardly from the side plate 16B. Advantageously, the plane of the earis parallel to the plane of the side plate and the plane of the earcoincides with the plane of the side plate. Apertures 16E are providedin the ear 16D and in the end plates 16A. The apertures 16E in the endplates 16A are positioned near the open side 16C.

[0022] While ear 16D may be welded in place, or be part of a cast ormolded bracket, advantageously bracket 16 is a unitary piece of wroughtmetal, with ear 16D coming from one of the end plates 16A, as shown bythe matching aperture in the neighboring end plate in FIGS. 3 and 4,this being done, for instance, by oxy-acetylene cutting along theoutline of the ear before the end plates are bent 90-degrees from theside plate, or by stamping or other form of shearing at the same timethat the end plates are being bent 90-degrees from the side plate.

[0023] One of the brackets is fastened to each end of each of the braces20, by inserting a carriage bolt of the fastener 18 through the aperture16E in the ear 16D, and completing the fastener 14 in a conventionalfashion, as shown in FIG. 3.

[0024] The method of installation of the bracket 16 will be describedherein by referring to the first ladder 12. The method is exactly thesame for installation on the second ladder 14. One of the brackets 16 isattached to the first leg 12C of the first ladder 12 by positioning theside plate 16B on an outward facing side of the first leg 12C, anddirecting the end plates 16A inward. Carriage bolts of the fasteners 18are inserted through the apertures 16E of the end plates 16A such thatthe bolts straddle the rung, with one of the carriage bolts extendsacross and above the rung 12A of the first ladder 12, and another of thecarriage bolts extends across and below the rung 12A of the first ladder12. This particular positioning of the carriage bolts through the endplates 16A ensures that the braces 20 cannot slip beyond the rungs 12Ain either an upward or a downward direction.

[0025] It is envisioned that the platforms 22 may be conventional woodenplanks, and the braces 20 may be conventional nominal 2×4 wood members.The braces 20 and the platforms 22 may be provided with the brackets 16,or the components may be purchased separately. For example, and not byway of limitation, the brackets 16 may be packaged with the fasteners 18with instructions for making the scaffold using a customer's own ladders12, 14, and using a customer's own wooden planks and members for theplatform 22 and braces 20.

[0026]FIG. 2 shows the scaffold on level ground. If the ground issloping, for instance so that ladder 12 is lower than ladder 14, blocksmay be placed under ladder 12, to bring it to the same height as ladder14, so that the carriage bolts of the brackets on ladder 12 willcorrectly straddle the rungs.

[0027] Interestingly, however, it has been discovered that the scaffoldof the invention is just as stable, even if the bolts do not straddlethe rungs. For instance, as shown in FIG. 2A, ladder 12 is somewhatlower than ladder 14, due to the fact that the ground is sloping. Bothladders are placed vertical, parallel to one another. The brackets 16are fixed to the rungs on ladder 14, as indicated by the fact thatbrackets 16 hide their associated rungs in the drawing on ladder 14,while the brackets 16 on ladder 12 are not fixed to the rungs, thisbeing indicated by the fact that all rungs of ladder 12 are visible inthe drawing. As long as the brackets are attached to the legs of ladder12, either slidably or fixedly, it does not matter that they lie in thespace between a rung above and a rung below, rather than being fixed toa rung. The scaffold is stable nevertheless.

[0028] With ladder 12 being lower than ladder 14 in FIG. 2A, platform 22slopes somewhat, because the rungs of ladder 14 are not be at the sameelevation as the rungs of ladder 12. It has been found, however, thatthe slope is small, even at its maximum, such that it does not disturbthe workers on the scaffold. In general, it is preferred to accept somedifference in the levels of the ladders, rather than to place blocksbeneath the lower ladder, because blocks can unexpectedly tilt out ofplace.

[0029] Carriage bolts often have a rounded head on top of a squarecross-section, although they may have hexagonal heads, as shown in thedrawings. Either form is acceptable for the invention. The apertures 16Efor the head sides of the carriage bolts have square cross-sections.These square cross-sections of the apertures cooperate with the squarecross-sections of the carriage bolts to keep the bolts from turning whenthe wing nuts are tightened.

[0030] FIGS. 5-7 illustrate the coordination of scaffolds of theinvention with buildings. In directions left and right in the plane ofFIG. 2, the scaffold is very stable. However, due to the relativelysmall breadth of the ladders (i.e. the relatively short lengths of theirrungs), it is preferred to tie the scaffold to a neighboring building,in order to guard against sway in directions perpendicular to the planeof FIG. 2.

[0031] Thus, in FIG. 5, the scaffold of FIG. 2 is tied to building 30 bystruts 32 a, 32 b fastened on the building side to rafters (not shown)beneath the eaves 34 and on the scaffold side to the braces 20.

[0032] The embodiment of FIG. 6 further improves stability by wrappingtwo scaffolds of the invention around the corner of the building 30, thetwo scaffolds being tied together by struts 32 c, 32 d fastened betweenthe braces 20 of the respective scaffolds. Here, the extreme north-southstability of the one scaffold extending north-south couples with theextreme east-west stability of a second scaffold extending east-west toform a unit reinforced against sway, this in addition to the swayresistance provided by the struts 32 a, 32 b.

[0033] As shown in FIG. 7, an advantage of the relatively small breadthof the ladders is that the scaffold of the invention fits betweenclosely spaced buildings 30 and 34. Here, resistance against sway isalso increased by struts 32 e, 32 f extending to the other building. Inthis case, it is also possible to use, instead of struts, taut cables 32a,b,e and f.

[0034] The foregoing description is included to describe embodiments ofthe present invention which include the preferred embodiments, and isnot meant to limit the scope of the invention. From the foregoingdescription, many variations will be apparent to those skilled in theart that would be encompassed by the spirit and scope of the invention.

[0035] For instance, while bolts represent a preferred fastener forfixing the end plates of the bracket relative to a rung, an alternativefastener may be comprised of a fork hinged to one end plate and whosetines can be swung to straddle a rung, with the ends of the tines thenbeing secured to the other end plate. Another alternative is a bicyclepadlock: the shackle of the padlock protrudes through the two holes ofone end plate, straddles the ladder rung, then protrudes through the twoholes on the other end plate and into locking engagement in the body ofthe padlock.

What is claimed is:
 1. Scaffold construction apparatus for creating ascaffold from ladders, comprising braces, brackets, fasteners and aplatform, the brackets comprising two opposed end plates, and a sideplate which spans between and connects the end plates.
 2. An apparatusas claimed in claim 1, the brackets further comprising an ear extendingoutwardly from the side plate.
 3. An apparatus as claimed in claim 2,the ear having an aperture for connecting one of said braces with one ofsaid fasteners.
 4. An apparatus as claimed in claim 2, the ear beingparallel to the side plate.
 5. An apparatus as claimed in claim 2, theear being coplanar with the side plate.
 6. An apparatus as claimed inclaim 5, the brackets comprising wrought metal, the ear coming from oneof the end plates.
 7. A bracket comprising two opposed end plates, aside plate which spans between and connects the end plates, and an earextending outwardly from the side plate.
 8. A method of constructing ascaffold, comprising attaching brackets as claimed in claim 4 onto twoparallel, vertical, broad-side facing ladders, with the side plate ofeach bracket on an outward facing side of a leg of the ladders, and theend plates directed inwards, and connecting a cross-brace to thebrackets on the ladders.
 9. A method as claimed in claim 8, furthercomprising fixing the brackets of the cross-brace on one of the laddersto rungs of that ladder.
 10. A method as claimed in claim 8, furthercomprising fixing the brackets of the cross-brace on both of the laddersto rungs of the ladders.
 11. A method as claimed in claim 9, furthercomprising fixing the brackets of the cross-brace on only one of theladders to rungs of that ladder, the brackets of the cross-brace on theother of the ladders being attached to the legs of that ladder betweenrungs.
 12. A method as claimed in claim 11, further comprisingconnecting the cross-brace at crossover.
 13. A method as claimed inclaim 8, wherein the cross-brace is connected to the ears of thebrackets.
 14. A method of stabilizing a scaffold constructed as claimedin claim 8, comprising tying the scaffold to a building.
 15. A method asclaimed in claim 14, wherein the scaffold is tied with a strut to thebuilding.
 16. A method as claimed in claim 14, wherein the scaffold istied to a second scaffold to wrap around a corner of the building.
 17. Amethod as claimed in claim 14, wherein the scaffold is tied between twobuildings.
 18. A method as claimed in claim 17, wherein the scaffold istied with struts to the buildings.
 19. A method as claimed in claim 17,wherein the scaffold is tied with cables to the buildings.